Equisetum horse tail spores (Equisetum arvense) Science Image

Ref: 80200206a



Horsetail spores. Coloured scanning electron micrograph (SEM) of spores of a horsetail (Equisetum arvense) plant. The spores (round) bear elaters (helical), which expand and contract with changes in humidity. Elaters help to tangle spores together into a clump called a propagule, and to dig the spores into the soil. Magnification: x350 when printed 10 centimetres wide.